There are many factors that affect the filtering performance of meltblown cloth, such as fiber linear density, fiber web structure, thickness and density. However, as the air filter material of the mask, if the material is too tight, the pores are too small, and the breathing resistance is too large, the user cannot inhale the air smoothly, and the mask loses its use value. Electrostatic electret process Because the filtration efficiency of ordinary melt-blown nonwoven fabrics is less than 70%
, the mechanical blocking effect of the three-dimensional fiber assembly of purely melt-blown ultrafine fibers with fine fibers, small voids and high porosity is not enough, so Melt-blown filter materials generally add electrostatic charge effect to the melt-blown cloth through the electrostatic electret process, and use electrostatic methods to improve the filtration efficiency, so that the filtration efficiency can reach 99.99%, which can be achieved with a very thin layer The expected standard, respiratory resistance is still small. 02 Electrostatic adsorption Electrostatic adsorption means that when the fibers of the filter material are charged, the particles are captured by the Coulomb force of the charged fibers (electret).
The current electrostatic electret methods mainly include electrostatic spinning method, corona discharge method, friction electrification method, thermal polarization method, low energy electron beam bombardment method, etc. The carriers are deposited on the surface of the meltblown cloth by the electric field. When the particles pass through various types of curved channels or paths, the fine dust is trapped The mechanically filtered van der Waals force is adsorbed on the fiber surface. When particles such as dust, bacteria and viruses pass through the filter material, the electrostatic force can not only effectively attract the charged particles, but also capture the neutral polarized particles with the electrostatic induction effect.9% to 99.
When the particle size is 3-Layer Face Mask Factory very small and the flow velocity is very low, the particles are trapped on the fiber due to the diffusion of Brownian motion and captured. This requires that the filter material not only improve its filtration efficiency, but also reduce its respiratory resistance as much as possible, and respiratory resistance and filtration efficiency are a contradiction. Become an electret filter material. The fiber diameter of the mechanically blocked polypropylene melt-blown cloth is 2 to 5 μm on average, and droplets larger than 5 μm in the air can be blocked by the melt-blown cloth. Part of the carriers will penetrate into the surface layer and be trapped by the trap of the electret masterbatch.